8 W actinic Heath moth trap

[bspadn]

Does anyone use an 8 W actinic Heath moth trap? If so, what sort of numbers do you catch with it? I've finally caught a few moths, but I'm a bit concerned that the light's not bright enough. And I'm guessing it won't be a simple case of buying a brighter bulb.......... (it'll probably need a new electrics system, etc.). Thanks!

[JKT]

It probably isn't bright enough. It needs to be in as dark place as possible to best effect. Also, that kind of lamp is not very good in low temperature. Whatever UV it is supposed to release (and I DO hope it is not a standard light) is reduced considerably in low temperature.

[bspadn]

Thanks. Hopefully the catches will improve as the air temperature increases. I bought the trap from here:

http://www.alanaecology.com/cgi-bin/sh0 ... 30#a014030

[Piers]

You can get a 40w tube for this type of trap, which will still run off a jelly acid battery.
You will need an inverter to convert 12V to 240V to make the 40W Heath trap portable, together with a 12v battery of at least 24ah.

Shop here (it's where Alana get their stock anyway).

Heath (actinic) traps are excellent if you are after quality rather than quantity, and of course significantly cheaper than a Robinson and a genny. In fact, for the price of a Robinson and a dencent genny, you could buy and run half a dozen of more Heath type traps simultaneously, which is handy if you have one night at a site with a variety of habitats to sample from.

With a little ingenuity Heath traps can also be raised to canopy height (use a tree surgeons ropes and 'biners) enabling you to sample from an area of the woodland that the MV trap can not.

The mortality rate is also significantly lower with a Heath trap, but it depends if that is a concern to you. Inadvertent death of a percentage of the catch seems to be par for the course in the name of recreational moth trapping, and perfectly acceptable. Not so recreational butterfly recording of course. Oh the duality of mankind.

Felix.

[bspadn]

Excellent, many thanks Felix, it's much appreciated! I think I'll see how I get on with the 8 W trap for the time being before deciding whether or not to upgrade. I'm new to mothing, so smaller numbers might not be a bad thing to start with! Andy

[Dave McCormick]

It probably isn't bright enough. It needs to be in as dark place as possible to best effect. Also, that kind of lamp is not very good in low temperature. Whatever UV it is supposed to release (and I DO hope it is not a standard light) is reduced considerably in low temperature.

Really, I have not noticed anything like that when using my actinic traps in cold weather as insect attracting actinics run cold rather than warm of normal actinics and won't crack in rain or frost.

I have a bunch of traps: 8W, 15W, 15W synergetic Green UV, 18W blacklight, 30W (actinics) 125W MV, 125W MV (clear bulb), 11/25W Energy Saving UV bulb, 15W 15.0 reptile vivarium (UVA/UVB) bulb and one that uses 1 green and 1 UV cold cathode and what I found out about 8W heath trap surprises me.

I used a 15W trap in an oak wood (lots of young oaks, mature oaks, mature ash, mature beech, lots of birch, grey sallow and scots pine) two weeks ago and then used a 8W trap in same place two days later and got the following results (I released moths from first time, far evough away from the trap site that they wouldn't easily come back to trap if close by):

First night (15W, low was 5C with cloud) 24 moths in 8 species:

6 Common Quaker
1 Clouded Drab
1 Twin-Spotted Quaker
2 March Moth
9 Chestnut
9 Hebrew Character
1 Agonopterix ocellana
1 Agonopterix heracliana

Next time using 8W Trap (3C min, dense fog) 81 moths in 11 species which outdid the 15W which was really surprising:

1 Red Sword-Grass
1 Early Thorn
31 Hebrew Character
14 Common Quaker
9 Twin-Spotted Quaker
11 Clouded Drab
2 March Moth
5 Early Grey
2 Satellite
3 Chestnut
2 Diurnea fagella

Although in March last year, one night in -3C low, clear sky I had 48 moths and again in -1C min weather, clear sky I had 51 moths both in 6W heath trap. I have used a 60W heath trap this time of year and got very little, so I think for Jan-April or early May, lower powered lights work better as its colder and you won't get moths flying as far as in summer/autumn months when it is warmer. Hebrew character the exception as it flies even in -7C or colder nights as I have had nights that were quite cold and had hebrew characters and nothing else.

You have to make sure the light you use is a BL350 (gives 350nm UVA out which attracts the moths) don't use a UVC or aquarium/pond actinic, its germicidal and kills bacteria and will kill moths and gives out dangerous amounts of UV radiation.

My main two portable traps are 8W and 15W traps. 15W uses a 24amp battery and 8W uses a 14amp motorcycle batteries. To calculate how long a light will last on a battery (the amount of amps is important as you want the light to last all night at any time of year): amps*voltage/watts (amps is amps on battery, voltage is voltage of battery which is 12 volts, watts is the watts of the light) so for my 8W this would be: 14*12/8= 21 hours however, lower powered lights such as energy saving ones will use less power than this and last a little longer and high powered lights use more and will last a little less than that.

I usually get my lamps/bulbs from Paul Batty here: http://www.pwbelg.clara.net/mercury/index.html

I use 2 8W car inspection lamps but use a 8W BL350 and 15W T5 BL30( 12 inch): http://www.lightbulbs-direct.com/produc ... 0-uv-tube/ tubes instead of the warm white one that it comes with, the lamps are behind a clear tube so won't get wet. I also use a 15W 12 inch synergetic green UV which is supposed to do better than a typical 15W Bl350 tube for attracting insects and I have seen some better results with it.

[bspadn]

Thanks for the advice Dave, very useful (and comprehensive!). I'm not sure what ampage my set-up is, but the battery is 12 V and the bulb 8 W. More often than not, the bulb's not on when I go out to empty the trap in the morning. Andy

[Dave McCormick]

You probably need a bigger amp battery then. I would also say that the 8W does better in early months as moths are reluctant to travel as far due to being colder, but as it gets warmer and moths venture out farther distances (such as out in open) a higher wattage bulb will be better such as a 125W MV or 40W actinic. 15W is probably about the best to use all year, but I use 8W when its colder in late Autumn and Winter, but for rest of year I use either the 15W or both 8W and 15W. The higher the wattage the light and the more UVA it gives off, the farther away the moths will see it..I wouldn't say higher the brightness but higher wattage as the 25W UV energy saving bulb gives of very little visible light and is the equivalent of a 120W normal bulb and if you photograph one when on, you'll defiantly see the UV given off by one is a lot.

[bspadn]

Thanks again, Dave. I've just checked and my battery is only 7 Ah, but it's what came with the trap, so should be OK. I'll see how I get on and probably upgrade at some point. Andy